1. Field of the Invention
The present invention relates to a 3D image display technology, especially to a 3D display device adopting a half-source driving structure.
2. Description of the Related Art
Because there is a distance between two eyes of a person, each of the eyes watches an object from a different direction. Therefore, a 3D display device uses human interocular difference to provide different images to the eyes, respectively, to generate a three-dimensional effect.
With reference to FIG. 1, a conventional 3D display system is disclosed and has a phase retarder film constituted by a patterned half-wave phase retarder layer 90 and a quarter-wave phase retarder layer 91 and mounted on a light-exiting surface of a liquid crystal display panel so as to output images having different polarization directions to an observer; and the observer wears a pair of polarized glasses 7 to receive the images having one polarization direction with his left eye and receive the images having another polarization direction with his right eye so as to create three-dimensional images in his brain. Generally speaking, the liquid crystal display panel of the 3D-display system uses images displayed by odd (or even) pixel rows as left-eye input images and images displayed by the other pixel rows as right-eye input images.
With reference to FIG. 1, images of the liquid crystal display panel of the 3D-display system will first travel through a polarizer to become linearly polarized images 80. The linearly polarized images 80 then travel through the patterned half-wave phase retarder film 90. Lights of the linearly polarized images will be separated into two sets of linearly polarized images 81 with mutually perpendicular polarization directions. The two sets of linearly polarized images 81 then travel through the quarter-wave phase retarder film 91 and output images 82 including left-handed circularly polarized images and right-handed circularly polarized images for being the left-eye input images and right-eye input images. Each of the lenses 71, 72 of polarized glasses 7 worn by the observer is constituted by a quarter-wave plates and a polarizer. The left-handed circularly polarized images and right-handed circularly polarized images 82 first travel through the quarter-wave plates of the lenses 71, 72 to be converted into linearly polarized images and then travel through the polarizers of the lenses 71, 72 and arrive at the left and right eyes, respectively. Because the polarizers of the lenses 71, 72 has different polarization directions, the user's left eye can only see the left-eye input images and the right eye can only see the right-eye input images. Hence, it can achieve a three-dimensional effect.
With reference to FIG. 2, FIG. 2 is a partial schematic view showing that a phase retarder film is correspondingly mounted on a liquid crystal display panel of a conventional 3D display system. The liquid crystal display panel of the conventional display system includes a plurality of gate lines 51, a plurality of data lines 50 being crossed with the gate lines 51 and a plurality of pixel region being defined by the gate lines 51 and the data lines 50. Each one of the pixel regions has a thin-film transistor and a pixel electrode 52 mounted therein. The pixel regions are divided into a plurality of pixel rows. The phase retarder film 60 has a plurality of first phase retarder areas 60A and a plurality of second phase retarder areas 60B, wherein the first phase retarder areas 60A and the second phase retarder areas 60B are alternately arranged with each other and have different liquid crystal orientations. Borders between the adjacent first phase retarder areas 60A and the second phase retarder areas 60B of the phase retarder film are respectively positioned between the adjacent pixel rows, and the borders between the adjacent first phase retarder areas 60A and the second phase retarder areas 60B are covered by black matrix 53 between the adjacent pixel rows.
With further reference to FIG. 3, since the cost of source driving circuits is higher than that of gate driving circuits, in order to reduce the use of source driving circuits, another conventional 3D display system adopts a pixel driving structure with half-source driver circuits. In the half source driver circuits, the number of the data lines 50 used in the source driving circuits is cut by half and each of the original gate line 51 is doubled to two gate lines 51a, 51b. Hence, the cost can be reduced while maintaining the same number of pixels by reducing the number of data lines in the source driving circuits.
However, in the pixel driving structure of half-source driving circuits shown in FIG. 3, when one of the pixel electrodes 52 is connected to a thin-film transistor which is positioned at an upper side of the pixel electrode 52, the adjacent pixel electrode 52 is connected to another thin-film transistors which is positioned at a lower side of this adjacent pixel electrode 52. Because space for each of the pixel region is fixed, two of the pixel electrodes 52 adjacent to each other in the same pixel row differ in light-exiting position. In order to cover the gate lines 51, the data lines 50 and the thin-film transistors, as shown in FIG. 4, the black matrix 53 will have regular convexity portions formed at two opposite sides of each gate line 51 and corresponding to the positions of the thin-film transistors for correspondingly covering those thin-film transistors. Thus, when the phase retarder film 60 shown in FIG. 2 is mounted with a positional error, the pixel electrodes 52 adjacent to each other in the same pixel row will differ in light transmittance area, and this will lead to a color washout problem to the 3D display system.
Therefore, it is necessary to provide a 3D display device adopting a half-source driving structure to overcome the problems existing in the conventional technology.